"Is the S Serisi S350d reliable, and what should you check?"
When buying a used Mercedes-Benz S-Class S350d 2017 (217 / 222), the most frequently mentioned issue: Oil cooler gasket leaks (OM642). Also, AdBlue system / NOx sensor / pump / injector failures are commonly reported.
Engines available in this year
Engine varies by trim; verify the engine code on the listing.
Listed from most frequently reported, each with its source.
Oil cooler gasket leaks (OM642)
Often reported
The oil cooler gaskets on the V6 OM642 engine degrade over time, causing oil leaks that accumulate in the engine's V-groove. Leaks are often not visible from above and can be mistaken for more serious issues like engine oil seals.
Engine Bay
AdBlue system / NOx sensor / pump / injector failures
Often reported
The SCR/AdBlue system in BlueTEC vehicles can experience various failures: NOx sensors reporting errors, clogged or faulty AdBlue pumps or injectors, and auxiliary components like heaters/valves failing. Symptoms include engine warning lights and performance limitation messages.
Exhaust Emissions
DPF clogging / DPF pressure sensors and incomplete regenerations
Often reported
The 3.0 BlueTEC engine uses a DPF/FAP filter. On city routes or many short trips, soot buildup and inability to perform passive/active regenerations are common, causing warning lights and messages.
Exhaust Emissions
Injector seals / 'black death' and leaks around injectors
Often reported
Some OM642 units report injector seal leaks, which can cause carbon buildup on the cylinder head ('black death'). Faulty seals can lead to fuel loss, oil dilution, exhaust smoke, and performance loss.
What should I look for when buying a Mercedes-Benz S-Class S350d?+
When buying a 2017 S350d, check the service history, test drive, and look for engine/transmission warnings. Most commonly reported issues: Oil cooler gasket leaks (OM642); AdBlue system / NOx sensor / pump / injector failures; DPF clogging / DPF pressure sensors and incomplete regenerations.
What are the common problems of the Mercedes-Benz S-Class S350d?+
Most frequently reported issues: Oil cooler gasket leaks (OM642); AdBlue system / NOx sensor / pump / injector failures; DPF clogging / DPF pressure sensors and incomplete regenerations.
Is the Mercedes-Benz S-Class S350d reliable?+
Rather than a simple yes/no, it's best to weigh the proven pros and cons together. This page lists 4 verified findings.
How does Carbeak collect data?+
The cards on this page are derived from the Difetti fault database; the source vehicle is matched to the target vehicle by brand, fuel type, engine, and generation. Topics with insufficient evidence are not shown.